Longwall mining machine



IAPYH 3, 1946. 'c. E. TIBBALS 2,399,073

'LONGWALL MINING MACHINE Filed Aug. 4, 1944 6 Sheets-Sheet l n AwInventor far/2&5

WW mm April 23, 1946.

c. E. TIBBALS LONGWALL MINING MACHINE Filed Aug. 4, 1944 6 Sheets-Sheet2 By M Q .v

l a y Inventor war/co April 23, 1946.-

C. E. TIBBALS LONGWALL MINING MACHINE Filed Aug. 4, 1944 6 Sheets-Sheet3 April 23, 1946' c. E. TIB BALS 2,399,073

I LONGWALL MINING MACHINE Filed Aug. 4, 1944 s Sheets-Sheet 4 Inventoraiwxwztzzam WW ttorneys April 6- I c. E TIBBALS 2,399,073

LONGWALL MINING MACHINE Filed Aug. 4, 1944 6 Sheets-Shqe't 5 0 f I i. i/7,}

C. E. TIBBALS LONGWALL MINING MACHINE April 23, 1946.

Filed Aug. 4, 1944 6 Sheets-Sheet 6 T awazmz By Q4.

WW ma Patented Apr. 23, 1946 UNITED STATES PATENT OFFICE 11 Claims.

This inventionrelates to an improved longwall mining. machineparticularly adapted to the retreat mining of coal pillars occurring ina relatively flat coal bed.

Present mechanical mining of coal involves a mining cycle of cutting,blasting, and loading. These operations require considerable manualeffort and they interfere with each other in highly concentratedconveyor mining, therebyresulting in low equipment and labor operatingefliciency. Also, each, coal handling operation decreases the lump coalyield and therefore the monetary realization from the product.

The object of the present invention is to combine the cutting andconveying of the coal-in one machine, and toeliminate the loading labor.All three of these operations are performed simultaneously, thus vastlyincreasing labor and machinery efliciency. As handling of the coalduring loading is eliminated, the. lump coal yield is increased.

More specific objects and features of the present invention will becomeapparent from the following description when considered in connectionwith the accompanying drawings, and the invention consists in the novelform, combination and arrangement of parts hereinafter more fullydescribed, shown in the drawings and claimed.

In the drawings, wherein like reference characters indicatecorresponding parts throughout the several views:

Figure 1 is a top plan view, partly broken away, of a mining machineconstructed in accordance with the present invention, and illustratingthe same as it appears in use.

Figure2 is a vertical section drawn on an enlarged scale, and partlybroken away, the plane of section being substantially on line 2-2 ofFigure l. V

Figure 3 is an enlarged transverse section taken on line 3-3 of Figure1.

Figure 4 is an enlarged fragmentary'plan view of the right hand portionof the construction shown in Figure 1.

Figure 5 is an enlarged fragmentary section taken on line 5--5' ofFigure 4.

Figure 6 is an enlarged section taken on line 6-6 of Figure 4.

' Figure? is an enlarged fragmentary plan view showingan edge portion ofone of the conveyor plates, with one of its louvered slots and two 01'its cutter bits..

' Figure '8 is a fragmentary section taken on line B BJofFI'gure 7. I

25 ment of the shaking conveyor.

10 invention consists of a combined shaking conveyor and under-cutterincluding a series of overlapping metallic plates l extending along theface of a coal pillar 2 and resting on the mine floor to form theconveyor. The edges of the plates next to the coalare fitted withreplaceable steel bits 3 to form a cutting edge. Socket members 3a arefitted and secured on the edges of the plates l next to the coal, andone bit 3 is secured in each socket member.

tend at such an oblique angle to the longitudinal axis of the shakingconveyor that the socket members force or plow coal dust away from theface onto the plates 1 during rearward move- These conveyor plates arereciprocated by a driving unit D in a manner similar to a-common shakingconveyor and are forced automatically against the coal to form anundercut 4, as and by a means to be later described. -It will of coursebe understood that the common shaking conveyor is reciprocated with arapid rearward movement and a slow forward movement to eiiect theforward travel of the coal.

A side member 5, consisting of channel iron sections, is fastened to theedge of the conveyor away from the coal to stiffen the plates l and toretain the coal on the conveyor. Bolt connections 6 areprovided betweenthe sections of the side member 5. The ends of the bottom plates Ioverlap but are not secured together for a considerable part of theirwidth, so that the conveyor is slightly flexible laterally. An anglebracing strip 5a. is provided between and riveted to each plate I andits associated section of side member 5 adjacent the outer edge of saidplate. The adjacent ends of these bracing strips may be overlapped, asshown in Figures 10 and 11. Louvered slots I are provided in the bottomplates I to remove dust that might collect under the conveyor. Theseslots are so arranged. that upon rearward movement of the conveyor thecoal dust will pass upwardly through the louvered slots 1 from beneaththe plates l.

The end. of the conveyor next to; thedrivin-g The back edges 20 3b ofthe socket members 3a, are beveled to ex- The ratchet wheels areoperated by a tension rod unit D is fitted with a pan 32 which iselevated at the discharge end to discharge the coal into a standardconveyor 33. The drive unit D is a standard shaking conveyor drive unitfitted with cut that after adjusting nuts 22 engage block 20, theconveyor will move rearwardly a greater distance than rod I9. This lagin rod I9 causes the relative displacement between the rod I9 and anauxiliary drive shaft 9 which is supported in 6 the conveyor so as to ineffect cause forward a heavy frame III. The shaft 9 is long enough topermit about five feet of lateral conveyor travel toward the face of thepillar with one set-up of the drive unit. A sleeve I I which carries adrive arm 12 is keyed at I3 to the shaft9 so as to permit the sleeve andthe driving arm to move laterally with the conveyor. Guide sleeve II andtransmit the lateral shaft stresses to the frame i0, and heavy screwjacks I5 are is set against the mine roof to hold. the drive unitrigidly in position.

The feed mechanism consists of a feed screw it located near each of theconveyor joints 6'. These feed screws are rotated by driving ratchetwheels I! supported in bearings I8 fastened to the side member 5 of theconveyor." Thrust washers 29 are placed between the ratchet wheels I!and the bearings I8 to receive the lateral pressure.

I9 which extends the full length of the conveyor and is slidablyconnected adjacent each joint 6' to the side member 5, as at I911, forlimited sliding movement relative to the latter; An adjusting nut 22 onthe tension rod I9 is arranged to strike a stop block fastened to thedriving arm I2,

so that when said adjusting nut strikes said stop block, the rod I9 ispulled forward to cause pawls 2| to rotate the ratchet wheels I'I, allbut one of said pawls being pivotedto ears on the rod I9 as at 21 a. RodI9 is held in tension by a heavy spring 23 at the back end of theconveyor; and the ratchet wheel next to the drive shaft 9 is operated bya short push rod '25 connected to rod I9 and carrying a further pawl 2|.Rod 25 is also connected to the side of pan 32 like red I9 18 connectedto member 5, as at I911. The rods I9 and 25 are slidably connected toplates 2 lb riveted on the upper flanges of side member 5 and pan 32,

both rods are flattened, as shown, where they are slidably connected tothe plates 2 lb.

As the feed screws l6 are rotated, they are fed toward the pillar 2 bythread boxes arranged to pivot in the bases of screw jacks 2'! engagedwith the floor and roof of the mine. Each-thread box 26 is mounted in aball 29 to permit the feed unit to pivot with the motion of theconveyor. A flexible coupling 30 is used to connecteach feed screw I6 tothe short shaft 3| of the adjacent or associated ratchet wheel. v

In operation, the coal is undercut by the'present machine and is thenbroken down onto the conveyor by suitable means such as compressed airpicks, hydraulic pressure tubes, or the use of explosives. As theconveyor and undercutter reciprocates, the broken down coal is movedforwardly and ultimately discharged from the pan 32 onto the conveyor 33for discharge at a desired remote point. The means for breaking the coaldown is not shown, as it may be awell known mining device. 7 As shownmore clearly in Figure 5, the block 20 is carried by the arm I2 adjacentthe inner end of the latter and adjacent the shaft 9,'while the outerend of arm I2 is pivoted at a to brackets 12 and b fixed to theadjacentside of pan 32. The spring 23 is anchored at oneend to the rearend of rod l9 and at its-other end to the rear end of the conveyou Itwill thus be appar- 2. Aconstruction as defined in claim 1, whereinshifting of pawls 2! relative to the conveyor, thereby rotating ratchetwheels I1. In this way, lateral adjustment of the conveyor andundercutter toward the pillar is effected upon completion of eachrearward movement of the conveyor and undercutter, thereby setting thecutter bits W 3 for the next cutting operation which results members I4carried by frame In slidably receives in deepening the undercut 4 eachtime the con- .veyor and undercutter moves forwardly or toward theconveyor 33.

, 'From the foregoing description, it is believed that the constructionand operation, as well as theadvantages of the present invention, willbe readily understood and appreciated by those 20 skilled in the art.Minor changes in details of construction illustrated and described arecontemplated such as fall within the spirit and scope of the inventionas claimed. I i WhatIclaimis: f f l. A longwall mining machinecomprising an elongated combined conveyor and undercutter including aplate'assembly adapted to be reciprocated upon the mine floor and havingdetachable undercutting bits mounted along one 'longi tudinal edgethereof and a'coal retainingwall mounted along the other longitudinaledge of the same, a driving unit for imparting longitudinalreciprocating movement to said conveyor and N undercutter with a 'quickrearward andslow forward motion, and means actuated by said' drlvingunit to automatically laterally, feed said conveyor and undercutteruniformly from end to' end toward the pillar being mined upon actuationof the .same by said'unitl: L

the conveyor and undercutter comprisesa plurality of plates mounted inend-to-end overlapping relation, and wherein the coal retaining wall Mis jointed to form the sole connection between said The rod 25 is weldedat one end to rod I9, and s plates, whereby the conveyor and undercutteris laterally flexible. r

3. The construction defined in claim 1, wherein the conveyor andundercutter comprises a plurality of plates mounted in end-to-endoverlapping relation, each plate being provided with a longitudinalseries of louvered slots to .permit upward passage of coal dusttherethrough upon rearward movement of the conveyor and undercutter. p p4. The construction defined in claim 1, wherein said last-named meanscomprises a tension rod extending longitudinally of the conveyor andundercutter at the outer side of the latter and provided atpredetermined intervals with pivoted pawls, a tension spring connectingthe rear end of said tensionrod with the rear end of said conveyor andundercutter, ratchet wheels mounted on and movable with the conveyor andundercutter and engaged by said pawls, and means to automatically effectrelative longitudinal movement between the tension rod and the conveyorand undercutterupon movement of the latter in one direction; saidfeeding means including screw jacks anchored in the mine and havingscrew shafts coupled to] said ratchet wheels for 'actuationby thelatter. r 5. The construction defined 'in' claim '1, wherein the drivingunit includes a driveshaft extending transversely of the conveyor,andunderciik ter, a frame fixed beneath saiddrive shaft, 9.

sleeve guided by said frame and movable longitudinally of the driveshaft, and an arm rigid with said sleeve and pivoted to the conveyor andundercutter, said sleeve being slidably keyed to said shaft to permitlateral adjustment of the conveyor and undercutter together with theactuating arm relative to the drive shaft.

6. In a longwall mining machine, an elongated combined conveyor andundercutter including a plate assembly adapted to be reciprocated uponthe mine floor with a rapid rearward and slower forward movement, socketmembers secured on the edge of said assembly adjacent the coal face andhaving oblique back edges disposed so that the socket members plow coaldust away from the coal face onto the plate assembly during rearwardmovement of the assembly, and cutting bits carried by said socketmembers. p

7. A longwall mining machine comprising an elongated shaking conveyorand undercutter including a plate assembly adapted to be reciprocatedupon the mine fioor and having detachable undercutting bits along theinner edge thereof and a coal-retaining wall along the outerlongitudinal edge portion of the same, and a driving unit connected tothe discharge end of the assembly for imparting longitudinalreciprocating movement thereto with a quick rearward stroke and a slowforward stroke.

8. The construction defined in claim 7,"in combination with transverselyarranged feedscrews disposed at spaced points along the outer edge ofthe assembly and having their inner ends journaled on saidcoal-retaining wall, ratchet wheels secured on the inner ends of saidfeedscrews,

an actuating element for said ratchet wheels including a rod slidablycarried by said wall and carrying pawls engaging the ratchet wheels,stationary feed nuts for said feed screws, and means operativelyconnecting said actuating element to the driving unit for moving saidactuating element longitudinally relative to the assembly so as to causethe pawls to turn the ratchet wheels and feed screws for feeding theassembly laterally toward the coal.

9. The construction defined in claim 7, in combination with transverselyarranged feed screws disposed at spaced points along the outer edge ofthe assembly and having their inner ends journaled on saidcoal-retaining wall, ratchet wheels secured on the inner ends of saidfeed screws, an actuating element for said ratchet wheels including arod slidably carried by said wall and carrying pawls engaging theratchet wheels, stationary feed nuts for said feed screws, and meansoperatively connecting said actuating element to the driving unit formoving said actuating element longitudinally relative to the assembly soas to cause the pawls to turn the ratchet wheels and feed screws forfeeding the assembly laterally toward the coal during the rearwardstroke of the assembly, said undercutting bits being arranged to have anundercutting action upon the forward stroke of the assembly.

10. The construction defined in claim '7, wherein the driving unitincludes a base plate having a guideway extending transversely beneaththe conveyor and undercutter, a driven rock shaft, a sleeve slidablyfitted in said guideway and slidably keyed on said rock shaft, and anupstanding arm rigid with said sleeve and pivoted to the conveyor andundercutter.

11. A longwall mining machine comprising an elongated combined shakingconveyor and undercutter including a plate assembly adapted to belongitudinally reciprocated upon the mine floor, detachable undercuttingbits mounted along one longitudinal edge of said assembly, acoal-retaining wall mounted along the other longitudinal edge of saidassembly, a driving unit for imparting longitudinal reciprocatingmovement to said assembly with quick rearward and slow forward strokes,said bits being arranged to undercut on the forward stroke, and meanstoautomatically feed the assembly laterally uniformly from end to endtoward the coal upon each rearward stroke of the assembly.

CHARLES E. TIBBALS;

